Flow capacity and ice cap stability of river channel in the Daqing River Basin of the South-to-North water diversion project during the ice period

Located in Baoding, northern China's Hebei Province, the Daqing River Basin faces a nonnegligible problem: the prevention and control of ice damage in the South-to-North Water Diversion Project (SNWDP) during the ice period. This paper sorts out the observation data on the ice conditions in river sections of the Daqing River Basin in winter, 1994-1997, and calculates the roughness of the water transmission sections, through mathematical calculation and inverse computation. On this basis, the authors analyzed the influence of ice caps on the flow capacity of river channel, and discussed the effects of water level variation on ice cap stability. The results show that, during the ice period, the ice caps in the upstream of the water transmission channel in the river basin are rougher than those in the downstream. In the same river section, the ice caps are rougher in the initial phase than the late phase. At the same water level, the flow capacity of different sections reduces by 40-61% under ice caps. For the entire river channel, the ice caps lower the flow capacity by 40-52%. The water level variation has a huge influence of ice cap stability. During the ice period, the flow should be maintained stable to transmit water under ice caps. This helps to stabilize water level, ensure the continuity and completeness of ice caps, and improve the water transmission efficiency in the ice period. (C) 2021 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Alexandria University.